Heavy duty tire with specified bead design

Abstract

An improved heavy duty pneumatic tire designed to be mounted on an associated design rim having a flange portion is described. The rim flange has an axially inward surface contacting the axially outward portion of the bead area of the tire and an axially outward radially extending outer surface. Each bead portion has a surface contacting a radially inner portion of the rim flange and one or more bead cores that extends radially above the radially outer surface of the rim flange.

What is claimed is:  
     
       1. A heavy duty pneumatic tire ( 11 ,  110 ) having a nominal rim diameter, an axis of rotation and a carcass ( 14 ), the carcass ( 14 ) having one or more cord reinforced plies ( 18 ) and a pair of bead portions ( 25 ), each bead portion ( 25 ), having at least one annular inextensible bead core ( 15 ,  150 ,  151 ,  250 ,  251 ,  252 ,  350 ) about which the cord reinforced plies ( 18 ) are wrapped, a tread ( 12 ) and a belt reinforcing structure disposed radially outward of the carcass, each bead portion ( 25 ) has a radially inner first surface ( 96 ) and a radially outwardly extending second surface ( 100 ), the first and second surfaces ( 96 ,  100 ) of the bead portion ( 25 ) being designed to engage a design rim ( 60 ), the design rim ( 60 ) having a pair of bead seat portions ( 92 ) and radially outwardly extending rim flanges ( 98 ), the tire ( 11 ,  10 ) when mounted on its design rim ( 60 ) being characterized by: 
       at least one bead core ( 15 ,  150 ,  151 ,  250 ,  251 ,  252 ,  350 ) in each head portion ( 25 ) extending from radially above the bead seat portion ( 92 ) of the rim ( 60 ) to radially outwardly beyond the radially outer surface ( 108 ) of the rim flange ( 98 ), the at least one bead core ( 15 ,  150 ,  151 ,  250 ,  251 ,  252 ,  350 ) in each bead portion ( 25 ) being inclined at an angle θ i  of greater than 30° from the radial direction at a radially outer apex  15 A to be substantially parallel to the ply path ( 19 ) and the one or more cord reinforced plies ( 18 ) has a ply turnup end ( 28 ) extending axially and radially outwardly from the at least one bead core ( 15 ,  150 ,  151 ,  250 ,  251 ,  252 ,  350 ), the at least one bead core having a spring-rate lowering layer inserted between a lower portion of the head core and an upper portion of the head core.  
     
     
       2. The heavy duty pneumatic tire ( 11 ,  110 ) of  claim 1  further characterized by: 
       the at least one bead core ( 15 ,  150 ,  151 ,  250 ,  251 ,  252 ,  350 ) in each bead portion ( 25 ) extending radially above the rim flange being formed from a single strand of monofilament steel wire ( 17 ).  
     
     
       3. The heavy duty pneumatic tire ( 11 ,  110 ) of  claim 1  further characterized by: 
       the at least one bead core ( 15 ,  150 ,  151 ,  250 ,  251 ,  252 ,  350 ) in each bead portion ( 25 ) extending radially above the rim flange ( 98 ) having a radially outer portion ( 15 A) that is triangular in cross-section and a radially lower portion ( 15 B) near the bead seat portion ( 92 ) of the design rim ( 60 ).  
     
     
       4. The heavy duty pneumatic tire ( 11 ,  110 ) of  claim 3  wherein the radially outer portion ( 15 A) of the at least one bead core ( 15 ,  150 ,  151 ,  250 ,  251 ,  252 ,  350 ) extending radially above the rim flange ( 98 ) has an axially outer surface ( 15 D) that is partially axially outward of the radially lower portion of the bead core ( 15 B). 
     
     
       5. The heavy duty pneumatic tire ( 11 ,  110 ) of  claim 1  further characterized in that: 
       the carcass ( 14 ) has one or more cord reinforced radial plies ( 18 ) wrapped about one bead core ( 15 ) in each bead portion ( 25 ), the one bead core ( 15 ) in each bead portion ( 25 ) extending from above the bead seat portion ( 92 ) to radially above the radially outer surface ( 108 ) of the rim flange ( 98 ).  
     
     
       6. The heavy duty pneumatic tire ( 11 ,  110 ) of  claim 1  further characterized in that: 
       the carcass ( 14 ) has a plurality of cord reinforced bias plies ( 180 ).  
     
     
       7. The heavy duty pneumatic tire ( 110 ) of  claim 6  wherein the bead portion ( 25 ) has two bead cores ( 150 ,  151 ), at least one bead core ( 150 ,  151 ) extending radially above the rim flange ( 98 ) are in each bead portion ( 25 ). 
     
     
       8. The heavy duty pneumatic tire ( 110 ) of  claim 6  wherein three bead cores ( 250 ,  251 ,  252 ) are in each bead portion ( 25 ), at least one bead core ( 250 ,  251 ,  252 ) in each bead portion ( 25 ) extending radially above the rim flange ( 98 ). 
     
     
       9. The heavy duty pneumatic tire ( 110 ) of  claim 8  wherein the bead cores ( 250 ,  251 ,  52 ) are sloped creating a radial interference between adjacent bead cores in each bead portion ( 25 ) of the tire ( 110 ).